Answer modes in push-to-talk mobile communication services

ABSTRACT

A method of operating a push-to-talk service over a mobile wireless communication network, where a user of a mobile wireless terminal may select an automatic or manual answer mode for incoming session invitations for at least some other users. The method comprises including in the push-to-talk session invitation sent from a calling party to a called party, a manual answer mode request, upon receipt of the session invitation at a push-to-talk server serving the called party, forwarding the invitation including the manual answer mode request to the called party regardless of any auto-answer mode setting for the called party, and receiving the invitation at the called party, and generating a ringing alert at the called party&#39;s terminal.

FIELD OF THE INVENTION

The present invention relates to the answer modes available inpush-to-talk mobile communication services.

BACKGROUND TO THE INVENTION

The Industry group know as the Open Mobile Alliance has developed a Pushto talk Over Cellular (PoC) specification aimed at enabling theprovision of services over standard mobile wireless communicationnetworks which resemble walkie-talkie services, i.e. at the push of abutton a subscriber can be instantly connected to one or more othersubscribers. PoC is currently defined in the documents published by theOpen Mobile Alliance: “Push to talk over Cellular (PoC)—Architecture”,Candidate Version 1.0—17, Mar. 2005, and “OMA PoC Control Plane”,Candidate Version 1.0—17, Mar. 2005. According to the PoC standards,voice data comprises talk “bursts” carried over a packet network, whilstthe signalling used to establish and control PoC sessions comprisesSession Initiation Protocol (SIP) signalling, also carried over thepacket network. PoC relies upon the IP Multimedia Subsystem (IMS)infrastructure provided within the networks of mobile operators. PoC isa specific implementation of the general push-to-talk (PTT) services.

FIG. 1 illustrates in very basic terms the PoC infrastructure whichfacilitates a PoC session between a pair of wireless terminals (SIPclients) identified as UE-A and UE-B. The UEs are attached to respectiveradio access networks (RAN-A and RAN-B), which in turn are connected toa packet-switched core network including an IP backbone. SIP signallingis routed through the IMS which includes SIP application servers actingas PoC servers. The UEs are registered with respective PoC servers(although it is possible that both UEs are registered with the same PoCserver).

The basic concept underlying PoC is the desire to allow one user to bealmost instantaneously connected to another user, so that a user justhas to press a call button and begin talking, with his or her voicebeing played out immediately on the other user's terminal. However, itwas appreciated at a very early stage in the development of push-to-talkservices that this may not always be desireable, at least from the pointof view of the called party. Provision was therefore made for theplaying of a ringing alert at the called terminal, in much the same wayas is provided for with conventional telephone calls (push-to-talkservices would still establish the session extremely quickly, much morequickly than conventional telephone calls can be established), withusers being given the option to select either the auto-answer mode orthe manual (ringing) answer mode.

According to the latest versions of the PoC standards, it is possiblefor a user (UserB) to register with his local PoC server, a “white” listof other user identities (UserA) for which the user wishes to apply theauto-answer mode. In the event that a PoC session is requested by one ofthe users on the white list, this is recognised by UserB's local PoCserver, and that PoC server includes an auto-answer flag in the SIPINVITE message that is forwarded to UserB. UserB's terminal detects theflag, and automatically returns the SIP 200OK (answer) message. Thesession is established. If the calling user is not on the white list (orno white list has been defined), a manual flag is included in the SIPINVITE forwarded to UserB's terminal. This is detected by the terminal,and a ringing alert played. The SIP 200OK is not sent by the terminal toits local PoC server until the user answers. IETF draft “A SessionInitiation Protocol (SIP) Event Package and Data Format for varioussettings in support for the Push-to-talk Over Cellular (PoC) service”,Miguel-Angel Garcia-Martin, draft-garcia-sipping-poc-isb-am-01,describes a method for notifying the local PoC server of the answer modeapplicable to users on the white list. A user switches between themanual and auto-answer modes by signalling the desired mode to the PoCserver using the SIP PUBLISH message as defined in the PoC standards.

This signalling process, including auto-answer mode setting and sessionestablishment, is illustrated in FIG. 2. Signalling flows in the userplane (e.g. the exchange of Talk Burst Control Protocol messages) is notshown in the Figure. The steps illustrated in the Figure are as follows:

-   -   1. The PoC Client B configures automatic mode in the network by        means of a PUBLISH request.    -   2. The PoC Server B acknowledges the automatic answer mode        setting by means of a 200 “OK” response and stores the ‘auto’        setting.

When the PoC User A presses the PoC button, the steps are as follows:

-   -   3. The PoC Client A decides to invite PoC User B to a PoC        Session and sends an INVITE request to the PoC Server A.    -   4. The PoC Server A sends the INVITE request to the PoC Server B        in the PoC User B Home Network.    -   5. The PoC Server B authorizes the PoC User A and selects the        configured answer mode and sends a 183 “Session progress”        response to the PoC Server A.    -   6. The PoC Server A sends a 200 OK response to the user A and        the PoC User A receives an indication that he can start to        speak.    -   7. The PoC Server B sends an INVITE request to the PoC Client B.        The INVITE request includes the request for automatic answer        mode.    -   8. The Client B accepts the invitation without prompting the PoC        User B.    -   9. The PoC Server B forwards the 200 OK to the PoC Server A.

The PoC standards define a mechanism for allowing a caller to override amanual answer mode setting specified by a called user. This involves theinclusion of a “MAO” parameter in the SIP INVITE message sent by thecalling user to initiate the PoC session. Upon receipt of an INVITEcontaining the MAO parameter at the called party's terminal, thatterminal automatically determines whether manual override is allowed forthe calling user. If so, then the 200OK answer is automatically returnedto the local PoC server, and the INVITE forwarded to the called userincluding the MAO parameter. If not, a ringing alert is played, and theanswer message only sent out if and when the called user answers.

SUMMARY OF THE INVENTION

The inventor of the present invention has recognised that it isdesirable to provide a mechanism in PoC for allowing a calling party tooverride an auto-answer mode setting at a called party's terminal, inaddition to the current mechanism for overriding a manual answer modesetting. This additional feature will be useful, for example, when acalling party wishes his words to be private, and wishes to avoid thesebeing played out on the called party's terminal for all those withinearshot to hear. The desire for an override mechanism applies also whena PoC User is invited to an ongoing PoC Session, or when initiating aPoC Session using a preestablished Session.

According to a first aspect of the present invention there is provided amethod of operating a push-to-talk service over a mobile wirelesscommunication network, where a user of a mobile wireless terminal mayselect an automatic or manual answer mode for incoming sessioninvitations for at least some other users, the method comprising:

-   -   including in the push-to-talk session invitation sent from a        calling party to a called party, a manual answer mode request;    -   upon receipt of the session invitation at a push-to-talk server        serving the called party, forwarding the invitation including        the manual answer mode request to the called party regardless of        any auto-answer mode setting for the called party; and    -   receiving the invitation at the called party, and generating an        alert at the called party's terminal.

Preferably, the signalling protocol used to establish and controlpush-to-talk sessions is the Session Initiation Protocol. The invitationthat contains the manual answer mode request may be the SessionInitiation Protocol INVITE or REFER message.

The push-to-talk session invitation may be forwarded by saidpush-to-talk server to the called party only following an authorisationprocedure carried out by the server. The method may also comprisecarrying out an authorisation procedure at a push-to-talk server servingthe calling party, the request only being included in the invitationforwarded to the push-to-talk server serving the called party ifauthorisation is granted. Either or both of the authorisation proceduresmay be carried out by comparing the identity of the calling party and/orcalled party against a list or lists of identities pre-stored at thepush-to-talk server(s).

Preferably, the method includes receiving a user prompt at the callingparty to request manual answer mode, and as a result including therequest in the invitation at the calling party. Alternatively, inclusionof the request could be automatically carried out, e.g. as a result ofpre-setting at the calling party.

The invention is applicable in particular to the push-to-talk overcellular service.

According to a second aspect of the present invention there is provideda method of operating a push-to-talk enabled mobile wireless terminal,the method comprising including a manual answer mode request in aninvitation sent by the terminal to a peer terminal

According to a third aspect of the present invention there is provided amethod of operating a push-to-talk server within a mobile wirelesscommunication network, the method comprising receiving a push-to-talkinvitation from a calling client terminal, the invitation including amanual answer mode request, forwarding the request including the manualanswer mode request to the called client terminal, and awaiting receiptof an answer message from the called client terminal before proceedingwith session establishment.

According to a fourth aspect of the present invention there is provideda mobile wireless terminal having a processor and memory configured tofacilitate participation of the terminal in a push-to-talk sessionfacilitated by a mobile wireless communication network, and a userinterface for allowing a user to interact with the processor and memory,the processor being arranged to receive a user input from the userinterface initiating a push-to-talk session, to generate a push-to-talkinvitation for sending to a called terminal and to include in theinvitation a manual answer mode request, and to send the invitation tothe called terminal.

According to a fifth aspect of the present invention there is provided apush-to-talk server for use in a mobile wireless communication networkto provide a push-to-talk service to wireless mobile terminals, theserver comprising:

-   -   an input for receiving a push-to-talk invitation from a first        wireless mobile terminal destined for a second wireless mobile        terminal, where the invitation may include a manual answer mode        request;    -   an output for forwarding a received push-to-talk invitation to a        second, destination wireless mobile terminal; and    -   a processor programmed to determine whether or not a received        invitation includes a manual answer mode request and, if so and        if an automatic answer mode has been set for the second wireless        mobile terminal, overriding the automatic mode setting and        forwarding the invitation to the second wireless terminal        including the manual answer mode request via said output.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates schematically a mobile wireless communication networkfacilitating a Push-to-Talk over Cellular service;

FIG. 2 illustrates signalling in the network of FIG. 1 associated withsession establishment in the auto-answer mode; and

FIG. 3 illustrates signalling in the network of FIG. 1 associated anauto-answer mode override procedure during session establishment.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

The push-to talk over cellular (PoC) service has been described abovewith reference to FIG. 1, and the manual answer mode override discussedwith reference to FIG. 2. The following discussion proposes theintroduction of a further override feature, namely an auto-answer modeoverride feature, the need for which has not previously been recognised.The person of skill in the art will appreciate that the widespread useof this new feature may require amendments of and/or extensions to thePoC specifications.

When a first PoC user (User A) wants to communicate with a second PoCuser (User B) using the manual answer mode, e.g. when User A does notwant to speak before User B is in a position where no other person canoverhear the conversation, User A can include in the invitation sent toUser B a request that manual answer mode be used, overriding anyauto-answer mode that User B may have put in place. FIG. 3 shows asimplified signalling flow example when a PoC User A invites another PoCUser B to a PoC Session and includes in the invitation a manual answermode request. This request has the form of the existing manual answermode request provided for in the PoC specifications (but currentlyintended for addition to the invitation only at the local PoC server ofUser A).

The answer mode is configured as follows:

-   -   1. The PoC Client B configures automatic mode in the network by        means of a PUBLISH request.    -   2. The PoC Server B acknowledges the automatic answer mode        setting by means of a 200 “OK” response and stores the “auto”        setting.

When the PoC User A presses the PoC button on his terminal, the stepsare as follows:

-   -   3. The PoC Client A decides to invite PoC User B to a PoC        Session and sends an INVITE request to the PoC Server A. The        manual answer mode is included in the INVITE request at Client        A.    -   4. The PoC Server A sends the INVITE request to the PoC Server B        in the PoC User B Home Network. The manual answer mode is        included in the INVITE request.    -   5. The PoC Server B sends an INVITE request to the PoC Client B.        The INVITE request includes the request for manual answer mode        received in the INVITE request from PoC Server A. The inclusion        of the manual answer mode indication instead of the configured        answer mode may be subject to authorisation at PoC server B,        i.e. to determine whether or not User B has authorised        auto-answer mode override by User A.    -   6. The PoC Client B sends a 180 Ringing response to the PoC        Server B and indicates to the PoC User B that a PoC Session        invitation has been received.    -   7. The PoC Server B sends the 180 “Ringing” response to PoC        Server A.    -   8. The PoC Server A sends the 180 “Ringing” response to the PoC        Client A. The PoC Client A indicates to the PoC User A that the        PoC User B is being informed about the invitation and that the        PoC Client B is waiting for PoC User B's acceptance, e.g. a        ringing tone is played at Client B.    -   9. When User B accepts the invitation, the PoC Client B sends an        INVITE request to PoC Server B.    -   10. The PoC Server B forwards the 200 OK to the PoC Server A.    -   11. The PoC Server A sends a 200 OK response to the user A and        the PoC User A receives an indication that he can start to        speak. The PoC session is established.

It will be readily appreciated that the procedure described here enablesthe calling client, PoC Client A, to influence the decision taken by thePoC Server B regarding the answer mode for Client B.

The procedure described here is equally applicable to a scenario inwhich a PoC User is invited to participate in an ongoing PoC Session,and in which a PoC Session is initiated using a preestablished session.In the latter case, the only significant difference to the approachdescribed above is that the manual answer mode request is included inthe REFER request sent by the PoC Client inviting the PoC User, ratherthan in the INVITE message.

It will be appreciated by the person of skill in the art that variousmodifications may be made to the above described embodiments withoutdeparting from the scope of the present invention.

1. A method of operating a push-to-talk service over a mobile wirelesscommunication network, where a user of a mobile wireless terminal mayselect an automatic or manual answer mode for incoming sessioninvitations for at least some other users, the method comprising thesteps of: including in a push-to-talk session invitation sent from acalling party to a called party, a manual answer mode request requestingsaid called party to answer an incoming session in said manual answermode; upon receipt of the session invitation at a push-to-talk serverserving the called party, determining at said push-to-talk server thatsaid manual answer mode request is included in said push-to-talk sessioninvitation and forwarding the session invitation including the manualanswer mode request to the called party regardless of any auto-answermode selling for the called party stored within said server; andreceiving the session invitation at the called party, and generating analert at the called party's terminal.
 2. A method according to claim 1,wherein the push-to-talk sessions uses Session Initiation Protocol assignaling protocol, and the invitation that contains the manual answermode request is one of Session Initiation Protocol INVITE or REFERmessages.
 3. A method according to claim 1, wherein the push-to-talksession invitation is forwarded by said push-to-talk server to thecalled party only following an authorisation procedure carried out bythe server.
 4. A method according to claim 3, wherein the authorisationprocedure is carried out by comparing the identity of the calling partyor the called party against a list of identities pre-stored at thepush-to-talk server.
 5. A method according to claim 1 further comprisingthe step of carrying out an authorisation procedure at a push-to-talkserver serving the calling party, the request only being included in theinvitation forwarded to the push-to-talk server serving the called partyif said authorisation is granted.
 6. A method according to claim 1further comprising the step of receiving a user prompt at the callingparty to request said manual answer mode, and as a result including therequest in the invitation at the calling party.
 7. A method according toclaim 1 further comprising the step of including said request at thecalling party automatically.
 8. A method according to claim 1, whereinsaid push-to-talk service is a push-to-talk over cellular service.
 9. Amethod of operating a push-to-talk server within a mobile wirelesscommunication network, the method comprising the steps of: receiving apush-to-talk invitation from a calling client terminal, the invitationincluding a manual answer mode request requesting a called party toanswer in said manual answer mode, forwarding an incoming sessionrequest including the manual answer mode request from said push-to-talkserver to a specified called client terminal regardless of anyauto-answer mode setting for the called client terminal, and awaitingreceipt of an answer message from the called client terminal in responseto said called client terminal being alerted of said incoming sessionrequest before proceeding with session establishment.
 10. The method ofclaim 9 wherein said push-to-talk invitation comprises a SessionInitiation Protocol and wherein said invitation including said manualanswer mode request is a Protocol INVITE or REFER message.
 11. Apush-to-talk server for use in a mobile wireless communication networkto provide a push-to-talk service to wireless mobile terminals, theserver comprising: an input for receiving a push-to-talk invitation froma first wireless mobile terminal destined for a second wireless mobileterminal, where the invitation may include a manual answer mode requestrequesting said second wireless mobile terminal to answer saidinvitation in a manual answer mode; an output for forwarding a receivedpush-to-talk invitation to said second, destination wireless mobileterminal; and a processor programmed to determine whether or not saidreceived invitation includes said manual answer mode request and, if soand if an automatic answer mode has been set for the second wirelessmobile terminal, overriding the automatic mode setting and forwardingthe invitation to the second wireless terminal including the manualanswer mode request via said output.
 12. The push-to-talk server ofclaim 11 wherein said push-to-talk invitation comprises a SessionInitiation Protocol and wherein said invitation including said manualanswer mode request is a Protocol INVITE or REFER message.
 13. Thepush-to-talk server of claim 11 wherein said output for forwarding saidreceived push-to-talk invitation is performed after an authorizationprocedure by comparing said first wireless mobile terminal or secondwireless mobile terminal against a list of identities pre-stored at saidpush-to-talk server.